A dual lithiated alloy interphase layer for high-energy–density lithium metal batteries

Lithium metal batteries represent potential candidates for high-energy–density batteries. However, non-uniform Li deposition and dendrite growth limit the practical applications of Li anodes in solid-state and liquid-phase battery systems. This report investigates the conversion mechanism of an aluminum coordination compound (Al(MMP)₃) at the interface of a lithium metal anode. Based on the proposed mechanism, a novel dual alloy comprising a Li_xAl-Li_xP hybrid interphase is designed to promote interfacial charge balance. Under the synergic effect of a fluoropolymer, the organic/inorganic protective layer containing the dual lithiated alloy exhibits short-term Li storage and rapid Li⁺ transport, thereby limiting the accumulation of inactive lithium and decreasing the Li⁺ migration barrier. Upon implementing the hybrid anode, the electrochemical life span of the Li metal battery exceeds 2000 h. Moreover, pairing with a Ni-rich cathode leads to excellent capacity retention and stable coulomb efficiency. The developed strategy can guide future advancements in lithium metal batteries with long cycle lives.